US2025262712A1PendingUtilityA1
Processing of scaled signals from in-situ monitoring system in chemical mechanical polishing
Est. expiryFeb 20, 2044(~17.6 yrs left)· nominal 20-yr term from priority
H10P 74/238H10P 52/403B24B 49/105B24B 37/013H01L 22/26H01L 21/3212
56
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
A conductive layer is monitored during polishing by an in-situ eddy current monitoring system. This includes repeatedly sweeping a sensor of the in-situ eddy current monitoring system across substrate such that each sweep generates a sequence of raw signal values that provides a trace and the repeated sweeping provides a sequence of traces. For each trace is scaled to generate scaled traces extending from a same start time or start position to a same end time or end position. A sequence of average traces is generated by calculating a running average of a multiplicity of consecutive scaled traces from the sequence of scaled traces. A sequence of estimated thickness values is generated based on the sequence of average traces. A polishing endpoint is detected or a polishing parameter is modified based on the sequence of estimated thickness values.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A computer program product for controlling a polishing system, the computer program product residing on a non-transitory computer readable medium and comprising instructions for causing one or more computers to:
during polishing of a conductive layer on a substrate, receive a sequence of traces from a sensor of an in-situ eddy current monitoring system, each trace being a sequence of raw signal values generated by sweeping the sensor across the substrate; for each trace of the sequence of traces, scale the trace to generate a scaled trace with each scaled trace extending from a same start time or start position to a same end time or end position, thereby generating a sequence of scaled traces; generate a sequence of average traces by calculating a running average of a multiplicity of consecutive scaled traces from the sequence of scaled traces; generate a sequence of estimated thickness values based on the sequence of average traces; and at least one of detect a polishing endpoint or modify a polishing parameter based on the sequence of estimated thickness values.
2 . The computer program product of claim 1 , comprising instructions to detect a leading edge of the trace and a trailing edge of the trace.
3 . The computer program product of claim 2 , wherein each raw signal value has an associated time or position value, and the instructions to scale the trace comprise instructions to, for each raw signal value, calculate an adjusted time or position value.
4 . The computer program product of claim 3 , wherein the instructions to calculate the adjusted time or position value Xa comprise instructions to calculate
Xa
=
(
Xp
-
X
2
)
*
(
X
4
-
X
1
)
/
(
X
3
-
X
2
)
+
X
1
where Xp is the associated time or position value, X1 is a normalized start time or position, X4 is a normalized end time or position, X2 is a start time of the raw signal value, and X3 is an end time of the raw signal value.
5 . The computer program product of claim 1 , comprising instructions to, for each average trace, subtract an underlying layer trace from the average trace to generate a modified trace.
6 . The computer program product of claim 1 , wherein the instructions to generate a sequence of estimated thickness values comprise instructions to convert signal values from a trace to thickness values using a correlation curve.
7 . A method of chemical mechanical polishing, comprising:
polishing a conductive layer on a substrate; monitoring the conductive layer during the polishing with an in-situ eddy current monitoring system, including repeatedly sweeping a sensor of the in-situ eddy current monitoring system across substrate such that each sweep generates a sequence of raw signal values that provides a trace and the repeated sweeping provides a sequence of traces; for each trace of the sequence of traces, scaling the trace to generate a scaled trace with each scaled trace extending from a same start time or start position to a same end time or end position, thereby generating a sequence of scaled traces; generating a sequence of average traces by calculating a running average of a multiplicity of consecutive scaled traces from the sequence of scaled traces; generating a sequence of estimated thickness values based on the sequence of average traces; and at least one of detecting a polishing endpoint or modifying a polishing parameter based on the sequence of estimated thickness values.
8 . The method of claim 7 , comprising detecting a leading edge of the trace and a trailing edge of the trace.
9 . The method of claim 8 , wherein each raw signal value has an associated time or position value, and wherein scaling the trace comprises, for each raw signal value, calculating an adjusted time or position value.
10 . The method of claim 9 , wherein calculating the adjusted time or position value Xa comprises calculating
Xa
=
(
Xp
-
X
2
)
*
(
X
4
-
X
1
)
/
(
X
3
-
X
2
)
+
X
1
where Xp is the associated time or position value, X1 is a normalized start time or position, X4 is a normalized end time or position, X2 is a start time of the raw signal value, and X3 is an end time of the raw signal value.
11 . A polishing system, comprising:
a platen to support a polishing pad; a carrier head to hold a substrate in contact with the polishing pad; a motor to generate relative motion between the carrier head and the platen; an eddy current monitoring system to monitor the substrate during polishing and generate a sequence of raw signal values that depend on a thickness of an conductive outer layer being polished and on thickness and/or conductivity of one or more underlying layers below the outer layer; and a controller configured to
during polishing of the conductive layer on the substrate, receiving a sequence of traces from a sensor of the in-situ eddy current monitoring system, each trace being a sequence of raw signal values generated by sweeping the sensor across the substrate,
for each trace of the sequence of traces, scaling the trace to generate a scaled trace with each scaled trace extending from a same start time or start position to a same end time or end position, thereby generating a sequence of scaled traces,
generating a sequence of average traces by calculating a running average of a multiplicity of consecutive scaled traces from the sequence of scaled traces,
generating a sequence of estimated thickness values based on the sequence of average traces, and
at least one of detecting a polishing endpoint or modifying a polishing parameter based on the sequence of estimated thickness values.
12 . The system of claim 11 , wherein the system is configured to detect a leading edge of the trace and a trailing edge of the trace.
13 . The system of claim 12 , wherein each raw signal value has an associated time or position value, and wherein the controller is configured to scale the trace by, for each raw signal value, calculating an adjusted time or position value.
14 . The system of claim 13 , wherein the controller is configured to calculate the adjusted time or position value Xa by calculating
Xa
=
(
Xp
-
X
2
)
*
(
X
4
-
X
1
)
/
(
X
3
-
X
2
)
+
X
1
where Xp is the associated time or position value, X1 is a normalized start time or position, X4 is a normalized end time or position, X2 is a start time of the raw signal value, and X3 is an end time of the raw signal value.
15 . A method of generating an underlying layer trace for use in in-situ monitoring, the method comprising:
bringing a calibration substrate into contact with a polishing pad on a platen, wherein the calibration substrate includes a dielectric layer having a top surface of which is exposed; rotating the platen and the carrier head with the calibration substrate in contact with the polishing pad; monitoring the calibration substrate by sweeping a sensor of an in-situ eddy current monitoring system across the calibration substrate to generate a sequence of reference traces with each respective reference trace of the sequence of reference traces corresponding to a respective sweep of a sequence of sweeps by the sensor, and wherein each reference trace includes a series of signal values; averaging the references traces to generate an averaged trace; storing the averaged trace as an underlying layer trace to be subtracted from a measured trace generated by the in-situ eddy current monitoring system during polishing of a device substrate that is covered by a conductive layer.
16 . The method of claim 15 , comprising conducting the monitoring of the calibration substrate with substantially no polishing occurring.
17 . The method of claim 16 , comprising flushing a polishing surface of the polishing pad with a cleaning liquid to remove slurry from the polishing surface before bringing the calibration substrate into contact with a polishing pad.
18 . The method of claim 16 , comprising venting a chamber in the carrier head holding the calibration substrate while the calibration substrate is in contact with the polishing pad.
19 . The method of claim 15 , wherein the sequence of reference traces includes 4 to 8 traces.
20 . The method of claim 15 , wherein scanning the scanning the sensor across the calibration substrate generates a raw signal trace, and comprising converting the raw signal trace to the reference trace using a correlation curve that relates signal values to thickness values.Join the waitlist — get patent alerts
Track US2025262712A1 — get alerts on status changes and closely related new filings.
We store only your email — no account needed. See our privacy policy.